Concrete Pipe Culverts - Nebraska Department of Roads

SECTION 720 -- CONCRETE PIPE CULVERTS720.01 -- DescriptionThis work shall consist of furnishing and installing new reinforced concrete culvert pipe(round, pipe-arch, and elliptical) and reinforced concrete slotted pipe and the relaying ofexisting reinforced concrete pipe at locations shown in the plans and in accordance with therequirements of these Specifications.720.02 -- Material Requirements1. The Contractor shall not order the pipe until a list of sizes and lengths isfurnished by the Engineer.2. Reinforced concrete culvert pipe shall conform to the requirements ofSection 1037.plans.List.3. Reinforced concrete slotted pipe shall conform to the requirements shown in the4. Approved preformed plastic gaskets are shown in the NDR Approved Products720.03 -- Construction Methods1. Excavation and backfilling shall be performed by the Contractor in accordancewith the requirements of Section 702.2. a. The Contractor shall lay the pipe true to established lines and gradeswith hub, bell, or groove ends upstream and spigot or tongue ends fully entered into theadjacent sections of pipe.b. All concrete pipe laid for drainage structures, except that which has beenmanufactured with tongue and groove ends, shall be made watertight with cement mortar(1-part cement and 2-parts sand).c. When a bell and spigot section of pipe is laid, the lower portion of thehub, bell, or groove of the preceding pipe shall be filled on the inside with sufficient mortar tobring the inner surface of the abutting pipes flush and even.d. After the pipe is laid, the remainder of the joint shall be filled and packedwith cement mortar; and sufficient additional material shall be used to form a bead around thejoint.e. The inside of the joint shall be wiped and finished smooth.f. After the initial set, the cement mortar on the outside shall be protectedfrom the sun with a moist earth covering.- 565 -

3. As an alternate to mortared joints, rubber gaskets or flexible plastic gasketsmeeting the specification requirements of AASHTO M 198 may be used if the design of thejoints is in conformance with this AASHTO designation.4. a. When concrete pipe is laid for an irrigation structure, full compressiongaskets conforming to the requirements of ASTM C 361 shall be used and installed on eachsection of the pipe as per the manufacturer's recommendations and standards.b. In the event that full compression gaskets are not available for the typeof pipe specified, a preformed plastic gasket for concrete pipe joints shall be supplied meetingFederal Specification SS-S-00210, "Sealing Compound, Preformed Plastic for Pipe Joints"Type 1, Rope Form.c. The Contractor shall hydrostatically test all precast concrete pipe laid forirrigation structures. Where the bottom grade of the pipeline at the outlet is less than 1.2 mabove the inside top of the pipe at its lowest point, no test will be required. Water for makingthe tests shall be furnished by the Contractor and shall be introduced into the siphons andpipelines in such a manner as to prevent rapid temperature drops in the pipe.d. Tests shall be made as soon after completion of construction of thestructure as practicable, but in no event sooner than 20 days after the placing of any concretethat will be subject to hydrostatic pressure during the test. Testing under full operating heador to heads designated by pipe classification will not be required, but the lines shall be testedto the maximum practical head by filling with water to the elevation of the bottom grade of theoutlet end or by other methods as directed by the Engineer. After the pipe has been filled tothe specified elevation, it may be allowed to stand for a period not to exceed 15 days tosaturate the pipe before testing. The test period shall be for 24 consecutive hours duringwhich time the water surface in the structure shall be maintained at the specified test elevation.e. The total amount of leakage during this 24 hour test period shall notexceed 20 L/mm of internal diameter per kilometer. If the leakage exceeds 60 percent of themaximum allowed, the Engineer may require the water to be maintained at the limitingelevation stated above for an additional period of 10 days to allow evidence of excessiveleakage at any point to become apparent. Individual leaks, evidenced by appearance ofmoisture, shall be repaired.f. The Contractor shall make all repairs or replacements, or both, that arenecessary to secure the required watertightness.g. The Contractor shall be responsible for any damage to the structures oradjacent works due to testing.h. The Contractor shall furnish all labor, equipment, materials, tools, water,and water-measuring apparatus required for making the tests; and the cost thereof shall beincluded in the unit bid price for the size of pipe being tested.5. Any pipe which is not true in alignment or to the established grade or whichshows any settlement shall be removed and reinstalled by the Contractor at no additional costto the Department.- 566 -

6. When the plans designate the extension of a concrete pipe culvert, theconnection shall be made by enclosing the connecting joint with a concrete collar. The collarshall be constructed in accordance with the requirements of Section 704; and the steelreinforcement shall be furnished, handled, and placed in accordance with the requirements ofSection 707. In all cases where a concrete headwall is in place, it shall be completelyremoved.7. Concrete culvert pipe which is designated to be relaid shall be cleaned ofaccumulations of soil and debris, hauled, and relaid in accordance with the methods hereindescribed for installing new pipe.720.04 -- Method of Measurement1. Excavation, concrete, and reinforcement for headwalls and collars will bemeasured for payment in accordance with the provisions in Table 720.01.Table 720.01Method of MeasurementRequirementsSubsectionExcavation for Structures.................................................................702.04Concrete ..........................................................................................704.04Steel Reinforcement ........................................................................707.042. See Subsection 718.04 for the methods to measure concrete pipe.3. Concrete pipe collar connections are measured by the cubic meter of concreteand kilograms of reinforcing steel used.4. At the junction of new concrete pipes, the measurement shall be extended tothe center of the pipe being tapped. This extension shall be the total allowance for building thejunction.720.05 -- Basis of Payment1. Payment for excavation, concrete, and reinforcement for headwalls and collarsshall be made in accordance with the provisions in Table 720.02.Table 720.02Basis of PaymentRequirementSubsectionExcavation for Structures.................................................................702.05Concrete ..........................................................................................704.05Steel Reinforcement ........................................................................707.05- 567 -

2. Pay Item Pay Unit____ mm Reinforced Concrete Pipe____ mm Round Equivalent ReinforcedConcrete Pipe____ mm Reinforced Concrete Slotted PipeRelaying Reinforced Concrete PipeClass _____ Concrete for Concrete CollarReinforcing Steel for CollarMeter (m)Meter (m)Meter (m)Meter (m)Cubic Meter (m³)Kilogram (kg)3. The cleaning and the hauling of the pipe from the site of removal or from theplace where it is stored to the point or points at which it is to be relaid will not be paid fordirectly, but shall be considered subsidiary to the work of relaying the pipe.4. Payment is full compensation for all work prescribed in this Section.- 568 -